package org.aplombh.java.interview.newcoder;

import java.util.Arrays;
import java.util.Scanner;

//HJ10 字符个数统计
public class HJ10_字符个数统计 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int[] b = new int[128];
        Arrays.fill(b, 0);
        String a = in.nextLine();

        char[] chars = a.toCharArray();
        for (char aChar : chars) {
            b[aChar]++;
        }

        int sum = 0;
        for (int i : b) {
            if (i > 0)
                sum++;
        }
        System.out.println(sum);
    }
}